Near Detectors for the Hyper-K Experiment Mark Hartz TRIUMF & - - PowerPoint PPT Presentation
Near Detectors for the Hyper-K Experiment Mark Hartz TRIUMF & Kavli IPMU TAUP 2019, Toyama, September 12 1 Near Detectors Hyper-Kamiokande Experiment Hyper-Kamiokande Water Cherenokov detector with 187 kton fiducial mass (8x larger than
Mark Hartz TRIUMF & Kavli IPMU
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TAUP 2019, Toyama, September 12
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Hyper-Kamiokande
Water Cherenokov detector with 187 kton fiducial mass (8x larger than Super- Kamiokande) Broad physics program including neutrino oscillations with accelerator neutrinos 1.3 MW beam from J-PARC (2.5x higher than current T2K beam power) New near/intermediate detectors to control systematic uncertainties
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Atmospheric neutrinos Nucleon decay Supernova relic neutrinos Solar neutrinos Supernova burst
Strong non-accelerator component of physics program:
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Current long baseline experiments observe 10s of neutrino and antineutrino candidates Hyper-K will observe ~2000 electron neutrino and electron antineutrino candidates each 3% statistical error on the CP violation measurement will be achieved Controlling systematic errors is critical: T2K’s current errors are ~6%
2058 events 1906 events
arXiv:1805.04163
Near detectors address uncertainties
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Current long baseline experiments observe 10s of neutrino and antineutrino candidates Hyper-K will observe ~2000 electron neutrino and electron antineutrino candidates each 3% statistical error on the CP violation measurement will be achieved Controlling systematic errors is critical: T2K’s current errors are ~6%
2058 events 1906 events
arXiv:1805.04163
Near detectors address uncertainties
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p π± νμ
(—)
μ±
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p π± νμ
(—)
μ±
Particle production modeling constrained by hadron production measurements
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p π± νμ
(—)
μ±
5
p
5
p π± νμ
(—)
μ±
Beam direction uncertainty = uncertainty in peak energy in off-axis beam
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p
5
p
Wrong-sign (defocussed) component of the beam is important background when searching for CP violation
π∓ νμ
(—)
μ∓
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n n n n n p p p p p n p ν l-
W+
p
Primary scattering process on a single bound nucleon Nucleon below threshold in water Cherenkov detector Energy inferred from charged lepton kinematics
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n n n n n p p p p p n p ν l-
W+
p
Primary scattering process on a single bound nucleon Nucleon below threshold in water Cherenkov detector Energy inferred from charged lepton kinematics
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n n n n n p p p p p n p ν l-
W+
p
Primary scattering process on a single bound nucleon Nucleon below threshold in water Cherenkov detector Energy inferred from charged lepton kinematics
p
Nuclear effects modify cross section and change energy inference Dominant source of systematic uncertainty
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n n n n n p p p p p n p ν l-
W+
p
Primary scattering process on a single bound nucleon Nucleon below threshold in water Cherenkov detector Energy inferred from charged lepton kinematics
p
Nuclear effects modify cross section and change energy inference Dominant source of systematic uncertainty
(Gev)
rec
E 0.5 1 1.5 2 2.5 Events 0.5 1 1.5
< 300 MeV
ν
0 MeV < E < 500 MeV
ν
300 MeV < E < 700 MeV
ν
500 MeV < E < 900 MeV
ν
700 MeV < E < 1100 MeV
ν
900 MeV < E < 1700 MeV
ν
1100 MeV < E
ν
1700 MeV < E
Feed-down from high energy is critical for θ23 measurement Need to measure the energy resolution function
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Lepton mass is also important For CP violation search: Muon neutrinos at near detectors Electron neutrinos at far detector >3% theoretical error on [σ(νμ)/σ(νe)] / [σ(νμ)/σ(νe)] Sources of theoretical error Phase space differences Form factor uncertainties in lepton mass dependent cross section terms Radiative corrections
Phys.Rev. D86 (2012) 053003
Fractional difference of electron (anti)neutrino and muon (anti)neutrino cross sections
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✦ On-axis detector: measure beam direction, monitor event rate ✦ Off-axis magnetized tracker: charge separation (measurement of wrong-sign background),
study of recoil system
✦ Expect upgrades of detector inherited from T2K will be necessary ✦ Off-axis spanning water Cherenkov detector: intrinsic backgrounds, electron
(anti)neutrino cross-sections, neutrino energy vs. observables, H2O target, neutron multiplicity measurement
On-axis Detector (INGRID) Off-axis Magnetized Tracker (ND280→ND280 Upgrade→??) Off-axis spanning intermediate water Cherenkov detector (IWCD)
Scin panel PVC vesse
50 m
Beam Direction
4º 1º
750 m
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✦ 14 modules in cross configuration on beam direction ✦ Iron and scintillator layers with 7 tons of target mass per module ✦ Monitor neutrino event rate to ensure stable beam operation ✦ Measure the beam direction with <0.25 mrad accuracy ✦ Uncertainty on predicted peak energy of neutrino spectrum <2 MeV
On-axis Detector (INGRID)
NIMA,V694, (2012), 211-223
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✦ T2K is in the process of upgrading the magnetized ND280 detector ✦ Planned installation in 2021 and operation from 2022 ✦ New Super-FGD and horizontal TPCs replace the P0D ✦ ND280 upgrade TDR: CERN-SPSC-2019-001 (arXiv:1901.03750)
TOF detector give better relative timing to improve direction measurement of particles
✦ A well understood detector from day one of Hyper-K operation ✦ Additional upgrades for Hyper-K for performance and longevity ✦ Upgrades informed by T2K measurement program
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✦ New TOF detectors allow to better
distinguish direction of high angle muons
✦ Necessary for wrong-sign measurement ✦ High-angle TPCs give full angular coverage
for track reconstruction
✦ Super-FGD target improves reconstruction
✦ Good timing and spatial resolution to
detect neutron scatters and reconstruct energy by TOF
✦ Improved capability to probe nuclear
effects and do calorimetric energy reconstruction
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PMTs Scintillator panel Readout electronics Stainless steel backplate PVC vessel
50 m
B e a m D i r e c t i
Acrylic dome
4º 1º
750 m ✦ 1 kton scale water Cherenkov detector located ~750 m from the neutrino production point ✦ Position of detector can be moved vertically to make measurements at different off-axis angle
to probe relationship of neutrino energy and final state lepton kinematics
✦ Can be loaded with Gd to measure neutron multiplicities in neutrino interactions ✦ Use multi-PMT photosensors with excellent spatial (80 mm) and timing (1.6 ns FWHM)
resolution
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(GeV)
0.5 1 1.5 2 2.5 3 3.5
5 10 15 20 25
1510 ×
Off-axis Flux ° 1.0
(GeV)
0.5 1 1.5 2 2.5 3 3.5
5 10 15 20 25 30 35
1510 ×
Off-axis Flux ° 2.5
(GeV)
0.5 1 1.5 2 2.5 3 3.5
5 10 15 20 25 30
1510 ×
Off-axis Flux ° 4.0
Spectra at at each off-axis bin Observed muon kinematic distributions Subtract off low energy and high energy sidebands of flux → produce very narrow beam to measure energy response. Measure non-quasi-elastic component with 5% uncertainty +0.4
(GeV)
rec
E 1 2 3 Events/50 MeV 2000 4000 6000
Event Spectrum µ 1 Ring Absolute Flux Error Shape Flux Error Statistical Error NEUT QE NEUT Non-QELinear Combination, 0.9 GeV Mean
(GeV)
ν
E 0.5 1 1.5 2 2.5 3
5 10 15 20
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10 ×
Linear Combination Off-axis Flux ° 1.7 Gaussian: Mean=0.9, RMS=0.11 GeV+1.0
Reconstructed neutrino energy (MeV) 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 100 200 300 400 500 600 700 800 900
Selected 1-ring e-like events
e
ν Other
µ
ν π
µ
ν NC Other π NC γ NC γ Entering signal
e
ν
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✦ Use intrinsic electron (anti)neutrino flux from
muon and kaon decays (<1% of beam)
✦ Water Cherenkov is ideal for the electron
(anti)neutrino cross section measurement
✦ Large active volume allows for veto of
background from externally produced high energy gammas
✦ Measurements at larger off-axis angle have high
flux fraction
✦ Simulation studies show 3.5-7% precision ✦ Reduction of systematic errors under
investigation
γ μ- γ π+
OD ID Sand
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✦ 1% level calibration is critical for IWCD ✦ Plan test experiment in tertiary beam to evaluate detector response and
calibration procedure
✦ Operation with p,e,π±,μ±, n with momentum range from
140 MeV/c-1200 MeV/c
✦ Planning operation at CERN after long shutdown (LS2)
4 m 4 m
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✦ The rich Hyper-K physics program will include precision oscillation
measurements and the most statistically powerful search for CP violation
✦ Controlling systematic uncertainties on modeling of neutrino flux and
interactions is critical
✦ Hyper-K plans a suite of near/intermediate detectors: ✦ INGRID - beam direction measurement and beam monitoring ✦ Upgraded ND280 - charge selection for wrong-sign measurement and
study of hadronic recoil system
✦ IWCD - Water target with measurements at varying off-axis angles and
measurements of electron (anti)neutrino cross sections
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